Aspects of obtaining forms of soluble organic calcium from the egg shell

Introduction. The shell of chicken eggs has long been used as a natural source of calcium in various food, feed, and pharmaceutical industries. There is a perspective to obtain soluble forms of calcium from the eggshell in the form of ascorbates, citrates, lactates, used in food technology as food additives that are obtained chemically. To date, the volume of eggshell produced in Russia is about 215 thousand tons per year, but the solubility of calcium from the shell is low, which does not allow the widespread use of this by-product of domestic production. One of the ways to increase the solubility of calcium can be considered the application of the process of mechanoactivation of the shell. The purpose of the study was to investigate the effect of the disintegration-wave action on the solubility of calcium shell eggs in organic acids in order to obtain soluble forms of ascorbates, lactates, and citrates.

Methods. The prepared shell of chicken eggs was milled on a disintegrator of the FED “Cedar 3601” grade and placed in solutions of organic acids until the calcium concentration values, determined by atomic-emission spectrometry with inductively coupled plasma (AES-ISP) using an Optima 2000 atomic emission spectrometer DV (Perkin Elmer) became constant.

Results. The existing data on the effect of mechanoactivation on the process of increasing the solubility of substances are analyzed. The effect of the disintegration-wave action on the solubility of the eggshell in organic acids is studied.

Discussion. The disintegration-wave action was found to have a significant effect on the solubility of the eggshell eggs in citric lemon, ascorbic and lactic acids. The greatest effect of mechanoactivation was established to be achieved with a two- or three-fold disintegration-wave action. The maximum solubility was observed at pH = 2.0-3.0. The maximum solubility was observed when dissolved in ascorbic acid at 90 °C, and in lactic and citric acids — at 60 °C.

Conclusion. Soluble forms of calcium obtained in the form of ascorbates, citrates, lactates, can be used in food technology as food additives. The application of the method of disintegration-wave action on the eggshell was established to increase the solubility of calcium in it. There are determined optimal settings, at which the maximum achievable values of calcium concentrations in systems are reached.